Hi Kierenc,
Nice to know you are pursuing this. Although I have always felt the Spider was a "Bit Large", my affection for it has continued to grow. So much so that I genuinely believe it to be a car that will still turns head 30 years from now. And the Q4, from my experience with my 159 is second to none - forget your Audi's, this system is the Bees Knees.
The engine however, has never been right, IMHO, but has the potential to be great. The Block is a masterpiece and the fact that it will continue, albeit with some changes, to be produced until 2026 speaks volumes for it. I am convinced that will not be the last we will see of it either. With the swing towards "Environmentally" friendly transport, there will not be the impetus to come up with new "drawing - board designs", so this engine could be pressed into further service beyond 2026.
However, back to your Spider!
I shall try to deal with your questions, not necessarily in the order you asked and I shall add a little by way of cautioning you about the overall cost.
The MAF issue has and continues to occupy quite some time. However, these issues revolve around code alarms and not engine performance. As you would expect, making modifications to the MAF, as I have done, is bound to affect performance. But they have been done; and continue to be done, to see how much more can be gained from my engine modifications. And also, I confess, to defer a visit to a good software company for remapping. But regardless of the issues surrounding the MAF, there is no question about the tremendous difference between my engine now and as it was prior to modification.
In every respect, I consider my 159 to be "Sports Saloon" and the engine, given I have exclusively owned Alfas for over forty years, performs better than any I have owned. It does not have the charisma of my 2.5 Alfetta GTV, but it has a balance which is extraordinary for such a big car. It can never be as great as the Busso V6, but it is better. The flexibility the VVT System brings to the engine can never be overstated. And while it does not sing the same song as the Busso, it's power is expressed in the exhaust note much more forcefully. It never runs out of breath as some variants of the Busso do, although the Busso can be made to perform extraordinarily well for such an old design. But, one mustn't detract from Busso's achievement and I still have my 3.0 GTV after all these years, unwilling to come to terms with parting with her.
It has been quite an exercise in resolving the MAF issues. But, I believe the Porsche MAF insert, 98660612501, AKA 0280218055, AKA 0280218192 suits the engine and as such it will remain my final choice. My original element, whatever it may be, is history and will remain so. It is also reassuring that the clip of the SW with C.B. cams and Brembo's has been well prepared after considerable money was spent on it and no doubt performs really well, particularly given the expense on the exhaust system, let alone all other components.
I recently posted on the Aussie site my latest thinking wrt the MAF and I now believe I have got my head around the issue of flow rates/AFR better than hitherto. The potential divider network using 2670 and 266 ohms gave noticeable better performance than the 330 and 2670 ohm resistors. Adjustments, I now realise, need to be incrementally small as one can go through the optimum point without realising it. And when all is said and done, I can always fit the Supersprint tail boxes to quieten the exhaust system a tad more.
It seems strange to say, but in truth the MAF issues have been at least the cheapest aspect of all the work which has gone into the engine. I firmly believe the Manifold Cats are real killers of this engine. I am informed by Autodelta that their headers can be fitted without the removal of the engine. However, as my spare Brera engine was being rebuilt it was not an issue for me. There will be a marked reduction in engine temperatures alone if only their removal is undertaken. But, as Supersprint pointed out the secondary cat under the car, being Ceramic, have a lower operating temperature and the catalytic wash could be stripped and cause blockages due to exhaust gas temperature after the Man Cats are removed. Particularly if valve timing is modified in the way that the C.B.'s do. One commentator has stated the angles are very much in the same territory as his Ferrari! Certainly, the sound they generate is glorious.
However, the work I have been doing surrounding the MAF has now led me to believe there is no issue with the Colombo Bariani Exhaust Valve Timing. My initial concerns were wrt the way the air is metered through the MAF with such a large PVO and the fact that the C.B. inlet is now open 0.5deg. BTDC, thus giving a complete induction stroke from TDC to BDC - volumetric efficiency being improved further given the inlet also closes later: compressive action of the rising piston upon the fast moving inrush of air through the inlet manifold, ably assisted by the massive valve overlap/scavenging and the Supersprint exhaust system, with sports cat.
But given at tick - over and under certain conditions the fuel is injected at, or around TDC on the compression stroke, the ECU has ample time to read the MAF flow rate and set the correct AFR, in conjunction with the wideband lambdas and certain other parameters. And I believe the C.B.'s will also afford a greater degree of accuracy of AFR - when the fuel maps are corrected, which will extrapolate as increased power output.
However Colombo Bariani confirmed to me, changing just the inlet camshaft would net an improvement only fifteen percent less than if all four camshafts were changed. With this in mind, whilst not maximising gains, considerable money could be saved with only a two cam (inlet) set up.
It could actually be cheaper as peculiarly Alfa have used hydraulic lifters of different heights on the inlet and exhaust camshafts, inlets being 34mm. and exhausts 37mm., if my memory serves me correctly. So fitting exhaust lifters to the inlet side, a regrind of the Alfa Inlet camshaft may well be possible. to achieve either a higher lift or a longer duration, whilst the Alfa Exhaust camshaft remains unchanged. And the exhaust lifters are more readily available.
Yes, the Colombo Bariani Camshafts are expensive and their performance is very much dictated by accuracy of valve timing. With this in mind, it is really essential to renew the timing chain system. I think you can see the direction this is heading. Combined with the very first issue I addressed wrt this engine, the tensioner system is not sufficient to maintain accuracy due to poor oil flow/pressure distribution across the block. Were I to do nothing else to this engine, I would definitely modify the oilways with supplementary lines - again. This, aside from improving chain tension, greatly improves the oil feed to the VVT System and makes a marked difference to its speed of operation.
Another problem with is engine is its relative low sump capacity. It is designed around four litres capacity but the return of spent oil from the system is very slow and the oil pick - up snout in the sump is quite high above the sump floor. At high revs, the level in the sump can dramatically drop and, particularly when the car is moving laterally, the pick - up can become exposed and the bearings suffer oil starvation. The latest version of this engine has a massively redesigned sump of much greater capacity. They have also included baffle/swage plates to ensure oil is always moving across the face of the pick - up, whatever direction the car is traveling in. In addition, they have extended the windage plate across the full length and I believe they have redesigned the return ducting for oil from the cylinder heads, away from the rotating crankshaft journals.
Simple modifications to the VVT Solenoids and the camshaft position sensor on the rear bank exhaust camshaft improve the accuracy of timing further. But, looking back, it seems such a daunting prospect. In truth, the mechanical side was very straight forward, especially given I had some fantastically good people involved - Scholar Engines, Fast Test, Brian Randal, Kevin Johnson, Supersprint, Autodelta, Mauro Bosio and Colombo Bariani, and numerous others who helped source parts.
Kierenc, you are about to undertake a project which will cost a lot of money. And I fear, you will not be satisfied with "Half Measures". That being the case, a spare engine may be the way to go, so you can progress it in an orderly pace and spread the cost over a longer period. But if you choose to go down the modification route, I would start with the Manifold cats. According to Autodelta, that will save about 8 bhp in losses, but your engine temperature will drop dramatically and it will stop destroying its oil. Intake air density will increase as temperature drops so actually it may well be worth 10 - 12 bhp.
I don't think accuracy of valve timing can be achieved and sustained long term unless the timing chain system and vvt's are addressed, which means "Oil Way Mods". Beyond that, C.B. cams are still high up the list, particularly as they can be reprofiled for even more performance. But, oil flow/pressure needs to be improved to get the best from the C.B.'s. Unless Mace have moved the Lobe centres I cannot see them being even better than Alfa's stock cams. Their blurb implies the cams give a pleasant exhaust sound but say nothing of increasing power. You pay for what you get and Mace are cheap, I suspect because they are more cosmetic than performance related. If the lobe centres stay the same - which I believe they do, and duration is less than Alfa's, then that won't generate PVO.
I hpe I have covered your questions. However, you can always PM me if there is anything you feel I may have omitted.
Kind regards,
Further to my above, I started this project with little knowledge of what I was letting myself in for. The improvement to the lubrication system I felt worthwhile but at that time had not anticipated the failure of my engine, which led on to the Brera rebuild.
However, knowing what I know now, would I undertake to do it all over again?
The answer to that question is, most definitely, YES. Having been back on the road again for a year tends to diminish the difference between my car now as opposed to how it was. So I must get to drive a standard 159 or Brera, which would bring home just how different the two are. None the less, the car feels right both for it's size and performance. It sounds so much sweeter, melodic even. But I understand the real cost of achieving this and couldn't recommend it to anyone that did not view the a car with the intention keeping it for a very long time.
Logically speaking, removing the man - cats and fitting Autodelta's would be a start. Removing the secondary cats and fitting a sports cat - Supersprint. - and their centre section could be a good second move. Then replacing the rear boxes, so that the whole system was much more free flowing, not having Alfa's central resonator.
A marked improvement would be achieved with these changes alone. which may then whet the appetite for replacing the camshafts. At which point, I believe it essential, to maintain valve timing accuracy, the timing chain system should be replaced with the uprated Mace system, whilst oilway and vvt modifications can be incorporated - without engine removal, to ensure one gets the best from the improved breathing and increased power the camshafts will bring.
It may not to be everyone's liking, preferring not to believe there are issues surrounding the oil flow/pressure, but throughout the time it has taken to rebuild this engine, so much more has come out of it to reinforce my belief that this issue alone is an overriding factor which limits how well this engine can perform.
